path: root/drivers/infiniband
diff options
authorJan Kara <jack@suse.cz>2013-10-04 09:29:06 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-04 10:56:16 -0800
commiteef5ed304aa7b49b8f58720855dd299163329db2 (patch)
treea60a6eca4bf65b5eddbc1001a25350eb9c4754f0 /drivers/infiniband
parent6aec95b47deb9e3dad4cb2e6db87f3b03544224d (diff)
IB/ipath: Convert ipath_user_sdma_pin_pages() to use get_user_pages_fast()
commit 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 upstream. ipath_user_sdma_queue_pkts() gets called with mmap_sem held for writing. Except for get_user_pages() deep down in ipath_user_sdma_pin_pages() we don't seem to need mmap_sem at all. Even more interestingly the function ipath_user_sdma_queue_pkts() (and also ipath_user_sdma_coalesce() called somewhat later) call copy_from_user() which can hit a page fault and we deadlock on trying to get mmap_sem when handling that fault. So just make ipath_user_sdma_pin_pages() use get_user_pages_fast() and leave mmap_sem locking for mm. This deadlock has actually been observed in the wild when the node is under memory pressure. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> [ Merged in fix for call to get_user_pages_fast from Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>. - Roland ] Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/infiniband')
1 files changed, 1 insertions, 6 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_user_sdma.c b/drivers/infiniband/hw/ipath/ipath_user_sdma.c
index f5cb13b21445..cc04b7ba3488 100644
--- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c
+++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c
@@ -280,9 +280,7 @@ static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd,
int j;
int ret;
- ret = get_user_pages(current, current->mm, addr,
- npages, 0, 1, pages, NULL);
+ ret = get_user_pages_fast(addr, npages, 0, pages);
if (ret != npages) {
int i;
@@ -811,10 +809,7 @@ int ipath_user_sdma_writev(struct ipath_devdata *dd,
while (dim) {
const int mxp = 8;
- down_write(&current->mm->mmap_sem);
ret = ipath_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp);
- up_write(&current->mm->mmap_sem);
if (ret <= 0)
goto done_unlock;
else {